Variables Affecting the Fracture Toughness of Dental Composites

Abstract

The fracture toughness of a variety of dental composites was evaluated using notched bending specimens, with and without pre-cracks. The pre-crack simulates more accurately a sharp, natural flaw in a material than does a notch, and is standard procedure in fracture-toughness evaluation. The fracture toughness was related to the filler composition and degree of conversion in the composite resins. In general, fracture toughness was highest in the more heavily filled resins, independent of degree of conversion in the matrix. The results also show that producing a pre-crack in certain composites reduced the value of their fracture toughness compared with notched-only specimens.

Get full access to this article

View all access options for this article.

References

Broughtman, L.J. and Sahu, S. (1971): The Effect of Interfacial Bonding on the Toughness of Glass Filled Polymers, Mater Sci Eng 8:98-107.

Carisella, J.B. ; Goolsby, R.D. ; and Hewitt, R.W. (1981): The Effects of Temperature and Moisture on the Mechanical Behavior of Reinforced Thermosets: I. Fracture Toughness of Neat Resins, Reinforced Plastics/Composites Institute, Proceedings of The Society of the Plastics Industry, Washington, DC, paper 7-c.

Ferracane, J.L. ; Matsumoto, H. ; and Okabe, T. (1985): Time-dependent Deformation of Composite Resins - Compositional Considerations, J Dent Res 64:1332-1336.

Goldman, M. (1985): Fracture Properties of Composite and Glass Ionomer Dental Restorative Materials, J Biomed Mater Res 19:771-783.

Hertzberg, R.W. (1976): Deformation and Fracture Mechanics of Engineering Materials, New York: John Wiley and Sons, pp. 274, 283.

Hornbogen, E. (1975): The Role of Fracture Toughness in the Wear of Metals, Wear 33:251-259.

Lambrechts, P. ; Ameye, C. ; and Vanherle, G. (1982): Conventional and Microfilled Composite Resins, Part II: Chip Fractures, J Prosthet Dent 48:527-538.

Lange, F.F. (1970): The Interaction of a Crack Front with a Second Phase Dispersion, Phil Mag 22:983.

Lange, F.F. and Radford, K.C. (1971): Fracture Energy of an Epoxy Composite System, J Mater Sci 6:1197-1203.

10.

Leinfelder, K.F. (1981): Composite Resins in Posterior Teeth, Dent Clin N Amer 25:357-364.

11.

Lloyd, C.H. (1983): Resistance to Fracture in Posterior Composites , Br Dent J 155:411-414.

12.

Lloyd, C.H. and Ianetta, R.V. (1982): The Fracture Toughness of Dental Composites, Part I: The Development of Strength and Fracture Toughness, J Oral Rehabil 9:55-56.

13.

Lloyd, C.H. and Mitchell, L. (1984): The Fracture Toughness of Tooth Coloured Restorative Materials, J Oral Rehabil 11:257-272.

14.

Roberts, T.C. ; Powers, J.M. ; and Craig, R.G. (1977): Fracture Toughness of Composite and Unfilled Restorative Resins, J Dent Res 56:748-753.

15.

Rosenfield, A.R. (1980): A Fracture Mechanics Approach to Wear, Wear 61:125-132.

16.

Smith, D.C. ; Pilliar, R.M. ; and Maric, B. (1983): Fracture Toughness and in vitro Wear Characteristics of Dental Composite Resins, J Dent Res 62:646, Abst. No. S16 (IADR).

17.

Spanoudakis, J. and Young, R. (1984): Crack Propagation in a Glass Particle-filled Epoxy Resin, Part I: Effect of Particle Volume Fraction and Size, J Mater Sci 19:473-486.

18.

Suh, N.P. (1977): An Overview of the Delamination Theory of Wear , Wear 44:1-15.

19.

Tani, Y. (1982): Marginal Fracture Toughness of Composite Resins , Dent Mater J 1:22-32.

20.

Wu, W. ; Toth, E.E. ; Moffa, J.F. ; and Ellison, J.A. (1984): Subsurface Damage Layer of in vivo Worn Dental Composite Restorations, J Dent Res 63:675-680.

21.

Yoshimoto, S. ; Nakajima, N. ; Kubota, A. ; and Iwamoto, T. (1985): Fracture Toughness of Posterior Composite Resin , J Dent Res 64: 179, Abst. No. 37.